Fuel receptacle isolation system for reducing the possibility of static discharge during the refill of high pressure storage tanks in motor vehicles
Apparatus for electrically isolating interconnecting station nozzle and vehicle receptacle components during the refueling of high pressure gas into a vehicle tank comprising an electrically isolated vehicle tank inlet receptacle engageable with a refueling nozzle wherein the receptacle includes an assembly of mutually engageable electrically insulating media in conjunction with the vehicle receptacle mount to prevent electrical contact from the refueling nozzle to the vehicle chassis and gas tank in the refueling gas flow conduit system.
This application claims the benefit of U.S. provisional application Ser. No. 60/713,023 filed on Aug. 31, 2005 which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTIONThe present invention relates to a system for eliminating the possibility of a static discharge during the refill of high pressure fuel storage tanks in hydrogen fuel cell powered vehicles.
BACKGROUND OF THE INVENTIONWhen hydrogen is used as a fuel in motor vehicles, a hydrogen fuel depot infrastructure for refueling must also be developed. Typically, present practice is that fuel is stored in on board tanks maintained at a maximum pressure in the range of about 5000 psi for hydrogen, and higher pressures in the range of about 10,000 psi or more are likely to be utilized in the future as the use of hydrogen becomes more widespread. During driving, a static charge may build up on the vehicle chassis. When the vehicle stops, the charge is usually dissipated to ground through the vehicle's tires; however, the rate of dissipation of the charge through the vehicle tires varies depending on the resistance of the tires and the resistance of the surface on which the vehicle is parked or stopped. If, at a refueling station or depot, the vehicle static charge energy is above a minimum threshold energy level that can cause the spark ignition of hydrogen gas, then it is unsafe to refuel the vehicle through the refill conduit connecting the fuel depot gas outlet and the vehicle tank inlet. If hydrogen were to leak at the depot refill nozzle or at the vehicle receptacle, a spark may occur when the refill nozzle is connected to the vehicle receptacle, which could potentially ignite the hydrogen. A conventional solution mitigates the static discharge problem, by manually connecting a grounding cable to the vehicle before refueling to avoid the potential for a spark to occur.
OBJECTS OF THE INVENTIONIt is an object of the present invention to isolate any charge potential that could be present on the vehicle chassis from the refueling receptacle, and thus reduce the possibility of a static discharge during the refill of high pressure storage tanks in hydrogen fuel cell powered vehicles at a retail outlet fueling depot.
SUMMARY OF THE INVENTIONThe invention is described more fully in the following description of the preferred embodiment considered in view of the drawings in which:
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The invention electrically isolates the refueling receptacle from the vehicle chassis. The electrically isolated receptacle is engageable with a refueling nozzle from the station depot side. The vehicle receptacle includes electrically insulating media to prevent electrical contact from the refueling nozzle to the vehicle chassis and gas tank. With reference to the description herein, the nozzle is an external fuel dispensing device that is connected to the receptacle; in describing the invention, “nozzle” refers to the station nozzle and the application should be so read contextually in the event of any ambiguity.
In Example A, a vehicle fuel receptacle is isolated from a vehicle body and tank system while allowing a secure conduit for high pressure fuel gas flow from the nozzle to the tank. An exterior vehicle tank inlet receptacle is engageable with the refueling nozzle; the receptacle has a vehicle body interior flange and a mating vehicle body exterior flange with a cylindrical extending section concentric with the interior flange leading to the fuel tank. The receptacle flanges are disposed to and fasten the section of the vehicle body upon which the receptacle is mounted; an insulating gasket is essentially coextensive with the exterior flange and the vehicle body. Concentrically extending sections of the flanges and gasket are secured with respect to the vehicle body by electrically non-conducting fasteners, or equivalently, by electrically conductive fasteners insulated from the flanges and vehicle body by insulating grommets. An o-ring may be disposed within the interior extending section of the interior flange adjacent the end of the concentric section of the exterior flange that extends within the interior flange. In an example, an insulating sleeve is disposed around the outer surface of the extending interior section of the exterior flange; the sleeve may extend beyond the end of the extending interior section of the exterior flange and fold inwardly at the end thereof to enhance insulating qualities.
In embodiments, a recessed o-ring is disposed within the interior extending section of the interior flange between the sleeve and the extending section of the interior flange or a pair of recessed o-rings, a first o-ring disposed within the interior extending section of the interior flange, and a second o-ring disposed within the interior extending section of the exterior flange, may be disposed within the flange sections such that the o-rings sandwich the sleeve. Based on design factors, one o-ring may be formed from a metal and the second o-ring may be formed from an electrically insulating material. The sleeve for the extending section of the exterior flange may be a cylindrical metallic collar having interior and outer surfaces covered with an electrical insulator and the insulator may comprises a surface coating of a polymeric material. O-rings may be longitudinally offset from, or aligned with, one another. The gaskets and insulator materials are preferably a nylon as described below.
The object of the invention is to isolate and minimize any electrical charge that could be present on the vehicle chassis and prevent the creation of a spark when the station nozzle is connected to the vehicle receptacle. Because the station nozzle is electrically grounded, if the receptacle on the vehicle is directly connected to the vehicle chassis, and the chassis still holds a static electrical charge, a spark can occur across the air gap as the nozzle approaches the receptacle while connecting the two during the refueling process. This spark could potentially ignite a hydrogen/air mixture that could be present due to a leak or other factors in the nozzle or receptacle areas. Normally the vehicle is grounded via a grounding cable or thru the vehicle tires before the nozzle is connected to the receptacle. However, the user may forget to or purposely avoid connecting the grounding cable prior to connecting the nozzle, or the fueling pad surface may have too high a resistance to adequately ground through the tires. When the receptacle is electrically isolated from the vehicle chassis, then there is little or no possibility for the electrical charge on the vehicle chassis to gap across to the nozzle and create a spark that may potentially ignite the hydrogen. The invention thus creates a safer refueling environment for the user and can be utilized as a secondary layer of protection in case the primary protection, dissipation of static electrical charge via grounding to earth, fails. In the discussion of the embodiments, reference numerals for elements of the vehicle receptacle and the fuel station connector to the receptacle that are initially identified in prior drawings may be omitted, both to avoid redundancy and for purposes of clarity in explaining the invention; however, their presence is evident in context.
An embodiment is shown in
In this example, the receptacle comprises a vehicle body flange having an exterior flange section disposed with respect to the vehicle body and an interior section extending from the exterior section toward the vehicle body interior. An insulating gasket is disposed between the exterior flange and the vehicle body in a sandwich relationship and a terminal is plate affixed to the interior extending end section of the vehicle body flange insulated by a gasket disposed between the end section of the vehicle body flange and the terminal plate. As in the above example, the flange, gaskets and plate are collinearly concentrically aligned such that an unobstructed fuel conduit is provided for high pressure hydrogen gas (or compressed natural gas). The exterior flange is insulated from the vehicle body by a flange in the gasket providing a central collar section extending over the inward extending section of the exterior flange from the vehicle body exterior. Fasteners securing the assembly, electrically insulate the receptacle from the vehicle body. In the embodiment shown, the plate gasket comprises a metal washer coated with an electrically insulating material and the plate gasket may be disposed between the aligned or offset o-rings. A reverse flange may be intrinsically formed at the interior facing end of the extending section of the exterior flange to receive a fastener for securing the plate with the insulator therebetween.
In
In
The mechanism of the invention thus isolates electrical charge that is possibly present on the vehicle chassis that could create a spark when the station nozzle is connected to the vehicle receptacle. The possibility is reduced that a spark could potentially ignite a hydrogen/air mixture that might occur due to a leak in the nozzle or receptacle areas. When the receptacle is electrically isolated from the vehicle chassis, the possibility for the electrical charge on the vehicle chassis to gap across to the nozzle and create a spark resulting in the potential ignition of hydrogen is reduced. The invention thus creates a safer refueling environment for the user and can be utilized as a secondary layer of protection in the event that the primary protection—dissipation of static electrical charge via grounding to earth—fails.
Having described the invention in detail, those skilled in the art will appreciate that, given the present description, modifications may be made to the invention without departing from the spirit of the inventive concept herein described. Therefore, it is not intended that the scope of the invention be limited to the specific and preferred embodiments illustrated and described. Rather, it is intended that the scope of the invention be determined by the appended claims.
Claims
1. Apparatus for electrically isolating a vehicle fuel receptacle from a vehicle body and tank system comprising: an exterior vehicle tank inlet receptacle engageable with a refueling nozzle; the receptacle comprising a vehicle body interior flange and a mating vehicle body exterior flange having an extending section interiorly concentric with the interior flange, the flanges disposed to sandwich the section of the vehicle body upon which the receptacle is mounted, the interior flange and the exterior flange affixed to the vehicle body by a plurality of fasteners insulated from the vehicle body wherein an insulating gasket essentially coextensive with the surface of the exterior receptacle flange is disposed between the exterior flange and the vehicle body.
2. Apparatus of claim 1 wherein the interior flange and the exterior flange and the insulating gasket are concentric and concentrically extending sections of the flanges and gasket are secured with respect to the vehicle body by electrically non-conducting fasteners.
3. Apparatus of claim 2 wherein the fasteners are electrically conductive and are insulated from the flanges and vehicle body by insulating grommets.
4. Apparatus of claim 1 including an o-ring disposed within the interior extending section of the interior flange adjacent the end of the concentric section of the exterior flange that extends within the interior flange.
5. Apparatus of claim 1 including an insulating sleeve disposed around the outer surface of the extending interior section of the exterior flange.
6. Apparatus of claim 4 wherein the sleeve extends beyond the end of the extending interior section of the exterior flange and folds inwardly at the end thereof.
7. Apparatus of claim 4 or claim 5 including a recessed o-ring disposed within the interior extending section of the interior flange between the sleeve and the extending section of the interior flange.
8. Apparatus of claim 4 or claim 5 including a pair of recessed o-rings, a first o-ring disposed within the interior extending section of the interior flange and a second o-ring disposed within the interior extending section of the exterior flange, the o-rings disposed within the flange sections such that the o-rings sandwich the sleeve.
9. Apparatus of claim 7 wherein one o-ring is formed from a metal and the second o-ring is formed from an electrically insulating material.
10. Apparatus of claim 4 or claim 5 wherein the sleeve comprises a cylindrical metallic collar having interior and outer surfaces covered with an electrical insulator.
11. Apparatus of claim 9 wherein the electrical insulator comprises a surface coating of a polymeric material.
12. Apparatus of claim 7 in which the o-rings are longitudinally offset from one another.
13. Apparatus of claim 7 in which the o-rings are longitudinally aligned with one another.
14. Apparatus for electrically isolating a vehicle fuel receptacle from the vehicle comprising a vehicle fuel tank inlet receptacle engageable with a refueling nozzle; the receptacle comprising (a) a vehicle body flange having an exterior flange section disposed with respect to the vehicle body and an interior section extending from the exterior section toward the vehicle body interior; (b) an insulating gasket disposed between the exterior flange and the vehicle body in a sandwich relationship; (c) a terminal plate affixed to the interior extending end section of the vehicle body flange; and (d) an electrically insulating plate gasket disposed between the end section of the vehicle body flange and the terminal plate; (e) the flange, gaskets and plate being collinearly concentrically aligned.
15. Apparatus of claim 13 wherein the insulating gasket disposed between the exterior flange and the vehicle body is flange shaped and has a central collar section extending over the inward extending section of the exterior flange between the outer circumference of the extending section and the vehicle body.
16. Apparatus of claim 14 wherein the circumferentially extending section of the exterior flange is concentrically aligned with the gasket and the flange and gasket are secured to the vehicle body by electrically insulating fasteners.
17. Apparatus of claim 14 wherein the circumferentially extending section of the exterior flange is concentrically aligned with the gasket and the flange and gasket are secured to the vehicle body by electrically conductive fasteners that are electrically insulated from the vehicle body by insulating grommets.
18. Apparatus of claim 13 wherein the plate at the exterior flange is concentrically aligned with the plate gasket and the flange and the flange and plate gasket are secured to the vehicle body by electrically insulating fasteners.
19. Apparatus of claim 13 wherein the circumferentially extending section of the exterior flange is concentrically aligned with the plate gasket and the flange and plate gasket are secured to the vehicle body by metal fasteners that are electrically insulated from the vehicle body by insulating grommets.
20. Apparatus of claim 13 wherein the plate gasket comprises a metal washer coated with an electrically insulating material.
21. Apparatus of claim 13 including a pair of concentric o-rings, a first o-ring recessed within the interior facing end of the extending section of the exterior flange, the second o-ring recessed within exterior facing end of the plate, wherein the plate gasket is disposed between the o-rings.
22. Apparatus of claim 15 or claim 16 including a reverse flange at the interior facing end of the extending section of the exterior flange having means for receiving therein a fastener for securing the plate.
Type: Application
Filed: Dec 13, 2005
Publication Date: Mar 1, 2007
Patent Grant number: 7715169
Inventors: Steven Mathison (Torrance, CA), Shiro Matsuo (Torrance, CA)
Application Number: 11/302,059
International Classification: B65B 3/04 (20060101);